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2 years ago

Please help me I have not gone over this in like 8 months and can not remember how to do it

Chemistry

1 answer:

Leona [35]2 years ago

4 0

Answer:

91%

Explanation:

Since you are just trying to find the yield, take the moles of the substance from the products and divide it by the mol value of the reactants. Multiply by 100 to find percentage

0.45 ÷ 0.41 = 0.91111...

91%

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What is the pOH of a solution of HNO3 that has [OH-] = 9.50 10-9 M?

bekas [8.4K]

Answer:

The pOH of HNO₃ solution that ha OH⁻ concentration 9.50 ×10⁻⁹M is 8.

Explanation:

Given data:

[OH⁻] = 9.50 ×10⁻⁹M

pOH = ?

Solution:

pOH = -log[OH⁻]

Now we will put the value of OH⁻ concentration.

pOH = -log[9.50 ×10⁻⁹M]

pOH = 8

Thus the pOH of HNO₃ solution that ha OH⁻ concentration 9.50 ×10⁻⁹M is 8.

6 0

3 years ago

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Predict the products of La(s) + O2(aq) ->

mina [271]

Answer:

i. La (s) + O2 (g) => LaO2 (s)

ii. La (s) + O2 (g) => La2O (s)

III. La (s) + O2 (g) => La2O3 (s)

Explanation:

Hello there!

When you are given such a problem for completing the chemical equations, what you have to understand is that metals are found in groups I, II and III. While Oxygen is a group VI element.

From the above question I have considered that my La(s), solid is either Sodium (Na) - group I, Magnesium - group II and Aluminum - group III.

In a reaction, there is exchange of electrons given by their oxidation numbers (I, II and III - for our metals above)

The chemical equations are thus;

i. Na (s) + O2 (g) => NaO (s)

ii. Mg (s) + O2 (g) => Mg2O (s)

iii. Al (s) + O2 (g) => Al2O3 (s)

Relate this to the problem and it will be;

i. La (s) + O2 (g) => LaO2 (s)

ii. La (s) + O2 (g) => La2O (s)

III. La (s) + O2 (g) => La2O3 (s)

I hope this helps you to understand better. Enjoy your studies

3 0

2 years ago

A certain isotope has 53 protons 78 neutrons and 53 electrons. What is its atomic number? What is the mass number of this atom?

statuscvo [17]

Answer:

53 protons
131g
Iodine
Halogens

Explanation:

atomic no. = no. of protons

= 53 proton

mass = no. of protons + no. of

neutrons

= 53 + 78

= 131

5 0

2 years ago

A potassium bromide solution is 8.30% potassium bromide by mass and its density is 1.03 g/ml. what mass of potassium bromide is

pshichka [43]

Answer: The mass of potassium bromide present in 41.2 mL of solution will be 3.522 grams.

Explanation:

We are given that KBr is present in 8.3% KBr solution, which means that 8.3 grams of potassium bromide is present in 100 gram of the solution.

To calculate the volume of KBr, we use the formula:

$Density=\frac{Mass}{Volume}$

Mass of the solution = 100 grams

Density of KBr solution = 1.03g/mL

Volume of the solution = ? mL

Putting values in above equation, we get:

$1.03g/mL=\frac{100g}{Volume}\\\\Volume=97.08mL$

Now, to calculate the mass of KBr in 41.2mL of the solution, we use unitary method.

In 97.08 mL of solution, mass of KBr present is 8.3 grams.

So, 41.2 mL of solution will contain = $\frac{8.3g}{97.08mL}\times 41.2mL=3.522g$ of KBr.

Hence, the mass of potassium bromide present in 41.2 mL of solution will be 3.522 grams.

7 0

3 years ago

Use the drop-down menu to complete the statement. The atoms in a ... have a definite volume, but move quickly enough to overcome

finlep [7]

Answer:

Luiquid

Explanation:

The atoms in a liquid state of matter have a definite volume, eventhough they acquire the shape of the container that contains them, the volume will always be the same, while in a solid the shape and volume will remain constant, on the other hand for a gas, the substance will fill the container where it is, having different volumes.

4 0

3 years ago

Read 2 more answers